Breakdown mill



AA ON BBBBBBBB LL May 5, 1 31.

A I i ammt1 May 5, 1931. A. PATERSON 1,804,111

BREAKDOWN MILL Filed Sept. 7, 1929 S Sheets-Sheet 2 Patented ay 5, 193i ALEXANDER PATERSON, OF BUFFALO, NEW YORK ennexnowu MILL Application filed September 7, 1929. Serial No. 391,045.

This invention relates to an improved breakdown mill for use in sheet and tin plate rolling.

In rolling sheet barsto breakdown gauge a preparatory to the rolling of packs it'has heretofore been the practice to use a mill having a single stand of rolls through which the piece is repeatedly passed until it has the ength and gauge by which it is adapted for further rolling as a part of a pack. In proceeding in this manner at least three 0perators and, depending on the weight of the piece, sometimes more,-are required, one operator catching the piece as it issues from the mill and returning it to another operator who feeds the piece through'the mill again while a third operator takes care of the necessary screw adjustment between the operations on each piece. To avoid loss and Waste of heat and to make the production as rapid as possible two pieces are usually ,fed in alternation through the mill, one piece being rolled while the other is being returned over the upper roll for further rolling; and

at the end of the roughing or breakdown operation these pieces are arranged as a pair or pack and further rolled.

T he foregoing procedure has long been recognized as slow, cumbersome and laborious. \Vith the most efficient and skilled workmen it usually takes from 30 to 50 seconds to roll a pair of sheet bars to breakdown gauge. Continuous mills are not practical for this work because the pieces handled are of such short lengths that they cannot be passed directly'from one roll stand to anotherhawing in mind the required roll di- 'an1'e'ters and the .necessary spacing of the 'roll stands. Tan em mills, are likewise impractical partly because of the complicated and expensive feeding equipment required and particularly in the pieces which are such as seriously to interfere with efficient rolling to breakdown gauge.

. Among the objects of the present invention are to overcome the disadvantages attendant on the use of existing breakdown mills and to provide for a 'greatl' increased production of breakdowns, for t e reduction of labor because of the heat losses and elimination of roll adjustments, for the square or true rolling of the pieces in all cases, and for the rolling of heavier sheet bars than can be handled by the present method, thereby enabling packs to'be formed by doubling over the breakdown sheetsproduced from such heavier sheet bars.

Further objects are to provide for the automatic succession of the rolling operations and for this purpose-to provide a mill which occupies a minimum length of floor space with reference to the number of roll stands employed.

For the maximum number of passes the complete breakdown mill embodies a novel arrangement and combination of mill units in each of which are incorporated novel features of construction and arrangement embodying improvements contemplated by the invention. Each unit has an arrangement of multiple roll stands, that is to say, two or three roll stands and. a air of such units may thus provide a com ination of five or six roll stands through which the pieces pass successively. In thepresent mill by virtue of their novel features of construction, two units will occupy an aggregate space of twenty to twenty-five feet in length.

The pieces will follow each other through the mill at intervals of one or two seconds andeach piece.will travel five or six feet or more per second so that in approximatelyv four or five seconds each sheet bar is reduced to breakdown gauge, the delivery of the breakdowns taking place at approximate intervals of one or two secondsf With the present mill, assuming a speed of three hundred andsixty feet per minute at the delivery rolls, if the. millbe occupied by the pieces only one-third of time, pieces aggregating .o'ne hundred and twenty feet at thedelivery end and each aboutfour feet long will be 'delivered per minute. That is to say, thirty breakdown sheets, or fifteen pairs are delive'red per minute as compared with three or four breakdown sheets or plates by the procedure heretofore followed.

Generally speaking, a" mill unit as contemplated by the invention is characterized by opposed integral housings, each having 100 windows for a multiple arrangement of roll stands together with means intermedi- 'ate the stands and successively cooperating with each of them for feeding and guiding the piece; although amill may consist of a single unit (providing the nature of the work permits suitable reduct on in a less number of passes) for ordinary use with pieces commencing at the sheet bar stage two units will be required and in such case suitable feeding and guiding means is provided intermediate and in cooperation with the units. The number of roll stands which may be incorporated in each unit is limited by the maximum permissible size and weight of the casting. Inasmuch as the rolls are extremely large and heavy and the stresses and strains incident to use are severe, strong and heavy castings are required and it is not deemed desirable or practical to incorporate more than three roll stands in a unit; beyond this number of roll stands the weight of the casting, having practical considerations in mind, would be prohibitive.

The multiple window housings enable a much closer juxtaposition of the reducing passes than has heretofore been possible while at the same time they have greater strength for support of the rolls and for taking up the stresses that may be developed. The reducing passes deliver the piece continuously forward and the rolls are so driven as to provide for this condition. The con veying rollers intermediate the reducing passes seize the piece before it is out of the pass behind and deliver it to the pass in front, remaining in engagement with it for a short time during its travel through said pass to which it is delivered. In this way a square or true feed of the sheet bar or plate is as sured as also the automatic passage of the piece through the series of roll stands at the end of which it has been reduced to the requisite break-down gauge. The reduction of the piece is accomplished much more rapidly than has been heretofore possible and the pieces to be reduced are fed to the mill much more rapidly than has heretofore been possible. For these reasons the mill has the many times increased productive capacity described. The close juxtaposition of the several roll stands assures of the travel of the piece through the millwithout serious radiation losses, that is to say radiation losses in such degree as will impair the rolling efficiency of the mill.

In the process heretofore used the convexity imparted to the piece by the central spring of the rolls must be gradually reduced in successive passes on the same stand of rolls and requires careful adjustment of the screw by operators skilled in the work. Vith the present mill in rolling a single piece it is not necessary that the successive passes be regulated to such a uniform. se-

quential reduction of convex section because in reducing the solid single piece greater screw reduction can be applied which distorts to some degree the uniformity of section between the passes. This lack of uniformity may be corrected by the last pass in which the piece is delivered with the required flatness, thereby automatically correcting the shape of the section.

The capacity of the mill for rolling breakdowns double the length which may be produced by the method heretofore used is of substantial advantage. For such double length breakdown a sheet bar of double weight is used. Such use of the double weight bar, in addition to a greater increased output, produces an important saving in scrap as compared with the use of two bars per pack.

The present mill may have roll stands of the two-high or three-high roll type, the latter being preferred, and the improvements may be utilized in connection with any auxiliary equipment, such, for example, as suitable means for cooling the rolls, suitable meansfor cooling the sheets, and a preliminary roughing mill such as is usually employed where extra heavy or thick sheet bars may be used. It will be understood that the breakdown sheets or plates produced by the present mill may be arranged in packs and rolled to finished gauge by a finishing mill of any suitable construction. \Vhere two units are employed to constitute the mill they may be both of the three-high roll type, both of the two-high roll type, or one of each type as circumstances may require. The roll stands may, of course, be of any suitable construction for the purposes in view.

The invention is illustrated in the accompanying drawings, in which Figure 1 is a diagrammatic view of a mill which consists of two units, each having three-high roll stands; in this view one unit is shown as consisting of three roll stands and the other of two roll stands but it will be understood that both units may consist either of two roll stands or of three roll stands.

Figure 2 is a central longitudinal sectional view of a unit embodying three stands of three-high rolls.

Figure 3 is a central longitudinal sectional I view of a unit embodying two stands of threehigh rolls.

Figure 4 is a diagrammatic View of a mill which consists of two units, each having twohigh roll stands.

Figure 5 is a central longitudinal sectional view of a unit embodying two stands of two-high rolls.

Figure 6 is a central longitudinal sectional view of a unit embodying three stands of twohigh rolls.-

Figure 7 is a side elevation of a unit of lit modified form embodying two stands of twohigh rolls.

Referring to Figures 1, 2 and 3 The mill is shown in Fig. l as consisting of a unit A embodying three stands of threehigh rolls, a unit B embodying two stands of three-high rolls, and sheet feeding and guiding equi ment C between the units.

The unit shown in Figure 2 includes roll housings 10 arranged in opposed relation in the usual manner but each of novel construction. Each housing 10 is ofintegral construction and is provided with three windows 11, 12 and 13, the windows 11 and 12 being separated by a bar 14 and the windows 12 and 13 being separated by a bar 15. The. windows 11, 12 and 13 permit a much closer juxtaposition of the roll stands than can be had with the arrangements heretofore used. The stands of rolls in the windows lliaud 13 are similar to one another and each consists of an upper .roll 16, an intermediate roll 17 and a lower roll 18. As shown, the upper roll 16 and the intermediate roll 17 are employed to roll the piece while the lower roll -18 reinforces the intermediate roll 17 The stand of rolls in the windows 12 is generally similar to the other stands and consists of an upper roll 16a, an intermediate roll 17a and a lower roll 1 8a. f In the particular form selected for illustration the intermediate roll 17a of the middle stand is of slightly less diameter than the intermediate rolls 17 of the other stands for a purpose to be hereafter described. However, the middle stand could be similar in all respects to the other two stands if so desired. The passes between the upper and intermediate rolls ofthe several stands may be regulated by screws arranged in the usual manner but as previously pointed out there is no necessity for regulating the passes to effect a uniform sequential reduction of the convex section of the piece since the correction of the section may be made by the last stand of the last unit.

The rolls may, of course, be driven in' 'any suitable manner. As shown, the driveincludes a gear 19 on the shaft which drives the upper roll 16a of the intermediate stand meshing with gears 20 and 21 on the shafts which drive the intermediate rolls 17 of the other two stands.

The unit is completed by sheet feeding and guiding meansarranged between the 216112.-

cent roll stands and consisting in each in-' stance of a feed drum 22 and a weighting rollcr 23, each drum 22 being driven conjointly by the lower rolls of the two adjacent stands. The pass of the'intermediate roll stand, by reason of the slightly smaller diameter of the roll 17a (as comparedwith the rolls 17) is slightly below the passes of the rolls of the other two stands and the pass of each 00- operating drum 22 and weighting roller 23 is in approximately the same plane as the pass of the intermediate roll stand. Thus the rolled portion of the sheet is deflected slightly downward as it issues from the first stand and is deflected slightly upward as it enters the pass of the last stand. The advantage of this arrangement is that it enables the use of a larger middle roll in the first pass where the heaviest .reduction is required. If desired, .however, the passes of the roll stands and of the two co-operating drums and weighting rolls may all be in the same plane. In the course of the travel of the piece through the pass of a roll stand behind, its forwardly extending portion passes between and is engaged by the adjacent drum 22 and companion weighting roller 23. Before the piece is disengaged by said drum and roller its forwardly projecting portion will enter the pass of the stand in front. In other words, the plece during its passage through this unit will at all times be engaged by two or more co-opera'ting pairs of roll elements, one pair being the active rolls of a roll stand and another pair being a drum 22 and its companion weighting roller 23. Hence the drum 22 and roller 23 constitute not only means for feedmg the piece but in co-operation with the roll stands constitute means for guiding the piece thereby assuring of a true or square feed of the piece through the unit.

' The unit B (Figure 3) includes roll housings 10a arranged in opposed relation in the usual manner and each of integral construction and provided with two windows 24; and 25 for the rolls. These windows are separated from one another by a bar 26 and provide the same advantage of a. closer juxtaposltion of the roll stands that is provided y the window arrangement of the unit A. The rolls of each stand are mounted in corresponding opposed windows, theupper roll 16?) and the intermediate roll 17 6 being employed to roll the piece while the lower roll 18b reinforces the intermediate roll 17 b The pass between-the rolls 16b and 17b of each stand may be regulated by screws arranged in the usual manner, the pass of the last stand of this unit being regulated to correct the cross section of the piece. The rolls may be driven in any suitable manner; for example, by engaging gears 27 on the shaft of the lower roll of one stand and the shaft of the upper roll of the other.

The sheet feeding and guiding means arranged between'the roll stands may be of the construction above described, the feed drum 22a being driven conjointly by the lower rolls of the two stands and being in cooperation with the weighting roller 23a arranged above it. The upper side of the drum 22a is approximately in the same plane as the upper side of the intermediate rolls 17b and the lower side of the roller 23a is approximately in the same plane as the lower sides of the rolls 166. In the course of the travel of obtained.

The sheet feeding and guiding equipment C may be of any suitable construction and is preferably one which will continue the true or square feed of the piece. it may also be driven in any suitable manner.. As shown, it consists of two feed drums 28 and 29 respectively, weighting rollers 30and 31 co operating with the respective drums, and a supporting roller 32 arranged between and rotating in the same direction as the feed drums. Vvhile the piece is engaged by the active rolls of the last stand of the unit A its forwardly projecting portion will pass bet-ween and be engaged by the feed drum 28 and the companion weighting roller 30; before the piece issues from between the drum 28 and roller 30its forwardly projecting portion will pass between and be engaged by the drum 29 and the companion roller 31; before the piece passes from between the drum 29 and roller 31 its forwardly projecting portion will pass between and be engaged by the activerolls of the first stand of-the unit B. Thus the equipment G not only feeds the piece but its feeding elements in co-operation with the adjacent rollstands and with one another constitute also means for guiding the piece, thereby assuring of a true or square movement of the piece from one mill unit to the other. After the piece issues from the last stand of the'unit B it may be placed in a pack and rolled to finished gauge 1n anysuitable manner and by any suitable mill.

The sheet bars are passed to the first stand of the unit A at intervals of one or two seconds and are advanced automatically through the mill in the manner described. The close juxtaposition of the roll stands provides for the travel of the piece through the mill without any serious radiation'losses and at a rapid rate. The rolls having been initially set for sheet bars of determined dimensions, no further setting is required for the operations of the mill on such sheet bars. Correction of the cross sections of the pieces may be made in the last stand of the last unit. Unusually heavy reducing pressures may therefore be exercised upon the piece in the preceding stands. The mill housings, being of integral construction, have all adequate strength for the support of the rolls and resistance to stresses, notwithstanding the provision in each housing of two or more windows. The showing oFthe-first unit of the mill as having three roll stands and the last unit as having two roll stands is, of course, merely rascal 1 i by way of example. If desired, the first unit may have two roll stands and the second unit three roll stands; or both units may have three roll stands; or both units may have two roll stands; or a single unit of three roll stands may be used either with or without a unit of one roll stand; or a single unit of two roll stands may be used either with or without a unit of one roll stand. It will be understood that the number of roll stands employed will depend on the particular circumstances and environment of use.

Referring to Figures, 4, 5, and 6:

The mill is shown in Figure 4 as consisting of a unit AA embodying two stands of twohigh'rolls, a unit BB embodying three stands of two-high rolls, and sheet feeding and guiding-equipment CC between the units.

The unit AA includes roll housings 10?) arranged in opposed relation in the usual manner and each of inegral-- construction and provided with windows 24a and 25a for the rolls. These windows are separated from one another by a bar 26a which permits the. described closer juxtaposition of the roll'stands. The rolls of each stand are mounted in corresponding opposed windows, the upper roll being designated 33 and the lower roll 34. These rolls may be driven in any suitable manner, for example, by gears 35 mounted respectively on the shaft which drives the upper roll of one stand and on the shaft which drives the lower roll of another stand. As in the construction first described, suitable means for feeding and guiding the piece is arranged between the rollstands. As shown, a pair of feed rolls 36 and 37 of relatively small diameters are arranged adjacent the first stand and a similar pair of feed rolls 38 and 39 are arranged adjacent the second stand. The

lower feed rolls 36 and 38 are active rolls and the upper rolls 37 and 39 are weighting rolls. The rolls 36 and 38 may be driven in any suitable manner. As shown they are driven by frictional peripheral engagement with an intermediate driving roll 40 arranged between and driven by the lower rolls of the two stands. The rolls 36 and 38 are preferably employed in connection with a guide table or frame 41 which bridges the space between the passes of the two stands.

Before the piece leaves the rolls of the first stand its rolled portion will pass between and be engaged by the feed rolls 36 and 37 before leaving the latter its forwardly projecting portion will pass between and be engaged by the feed rolls 38 and 39; before leaving the latter its forwardly projecting portion will pass between and be engaged by the rolls of the second stand. Hence, the piece will always be engaged by at least two sets of rolls, thereby insuring a true or square feed of the piece through the unit.

The unit BB shown in Fig. 6 includes roll housings 100 arranged in opposed relation in the usual manner and each of integral construction and formed with three windows 11a, 12a and 1311, the windows 11a and 12a being separated by a bar 14a and the windows 12a and 13a being separated by a bar 15a. The windows 11a, 12a and 13a of the unit BB provide the same advantage of a closer juxtaposition of the roll stands that is provided by the windows 24a and 25a of the unit AA. The stands of rolls in the windows 11a, 12a and 13a are similar to one another and to the stands of rolls of the unit AA and each consists of an upper roll 33a and a lower roll 34a. The rolls may be driven in any suitable manner, the drive as shown consisting of gear 19a'on the shaft which drives the upper roll of the intermediate stand and gears 20a and 21a on the shafts which drive the lower rolls of the first and'last stands.

A The unit is completed by sheet feeding and guiding means arranged between the adj acent roll stands. Such means is' shown as of the same construction as the sheet feeding and guiding means of the unit AA and as driven and operated in the same manner and with the same effects.

The sheet feeding and guiding equipment CC between the units may beof any suitable construction. As shown it is of the same construction andis driven in the same manner and operated with the same effects as the sheet feeding and guiding mechanism C of the mill shown in Figure 1. It therefore requires no detailed description, it being sufficient to point out that it continues the true and square feed of the pieces from the unit AA to .the unit BB in the manner above described.

Referring to Figure 7 In.the constructions previously described I have shown the windows as separated by continuous bars. The continuity of the'sep- "arating bars is, however, not indispensable and in Figure 7 I have shown a unit consisting of two stands of two-high rolls wherein the separating bar 261; is cut away at the center as at 260. The construction of the housings in'this manner has the advantages of giving easier access to the sheet feeding and guiding mechanism intermediate the stands and of enabling the observation of the piece as it passes from one stand to'another. If, for example, due to any unfore-, seen irregularity in the form of the piece or in the roll action, a piece should tend to jam or get out of line or otherwise not pass in roper manner through the unit ready access may be had through the cut-away portions 260 to the piece or to the feed rolls-in order to correct the trouble. Where cut-away -por-- tions such as the portions 260 are provided strength and .to compensate for the loss of the bracing effect of the integral separating bars between the windows occasioned by the provision of the cut-away portions.

Having fully described my invention, I claim:

' 1. A sheet bar breakdown mill including a unit comprising opposed integral housings, each having more than one window, the windows of one housing registering with the windows of the other, astand of rolls fitted in each pair of registering windows, and, work feeding means between the roll stands for transferring the piece from the stand behind to the stand in front, said feeding means being so arranged relatively to said, roll stands that it engages the piece before it housing registering with the windows of the other, and the roll stands of such unit several- 1y fitted in the pairs of registering windows in combination with work feeding means between the units and so arranged relatively thereto as to engage the piece before it leaves the unit behind and to maintain its engagement with the piece for a while after it enters the unit in front.

3. A sheet bar breakdown mill including two juxtaposed units provided with roll stands through which the piece passes successively, at least one of the units including opposed integral housings, each having more than one window with the windows of one housing registering with the windows of the other and the rollstands of such unit severally fitted in the pairs .of registering windows, and work feeding means between such roll stands for transferring the piece from the stand behind to the stand in front, said feeding means being so arranged relatively to said roll stands that it engages the piece before it leaves the stand behind and maintains its engagement with the piece for a while after it enters the pass of the stand in front, in combination with jwork feeding means between the units and so arranged relatively thereto as to engage the piece before it leaves the unit behind and'to maintain its engagement with the piece for a while after it enters the unit in front. I i

4. A sheet bar breakdown mill including a unit comprising opposed integral housings, each having more than one window, the windows of one housingregistering with the windows of the other, a stand of rolls fitted in eachpair of'registering windows, and work feeding means between the roll stands for in each pair transferring the piece from the stand behind to the stand in front, and including a driving element driven from rolls of the adjacent stands, said feeding means being so arranged relatively to said roll stands that it engages the piece before it leaves the stand behind and maintains its engagement with the piece for a while after it enters the pass of the stand in front.

5. A sheet bar breakdown mill including a unit comprising opposed integral housings, each having more than one window, the windows of one housing registering with the windows of the other, a stand of rolls fitted in each pair of registering windows, and work feeding means between the roll stands for transferring the piece from the stand behind to the stand in front, said feeding means being so arranged relatively to said roll stands that it engages the piece before it leaves the stand behind and maintains its engagementwith the piece for a while after it enters the pass of the stand in front each housing having the division bar between its Windows provided with a cut-away portion to give access from either side of the unit to the sheet feeding means.

6. A sheet bar breakdown mill including a unit comprising opposed integral housings, each having more than one window, the windows of one housing registering with the windows ofithe other, a stand of rolls fitted of registering windows, and work feeding means between the roll stands for transferring the piece from the stand behind to the stand in front, said feeding means including an element engaging the surface of a roll of one of the stands and being driven thereby, said feeding means being so arranged relatively to said roll stands that it engages the piece before it clears the stand behind and maintains its engagement with the piece for a while after it enters the pass of the stand in front.

7. A sheet bar breakdown mill including a unit comprising opposed'integral housings, each having more than one window, the Windows of one housing registering with the windows of the other, a stand of rolls fittedin each pair of registering windows and consisting of upper and lower working rolls and a reinforcing roll below the lower working roll, and work feeding means between the roll stands for transferring the piece from the stand behind to the stand in front, said feeding means including a feed roll engaging with and driven by one of the reinforcing rolls and a weighting roller co-operating With said feed roll whereby the piece is engaged before it leaves the stand behind and for a while after it enters the stand in front.

In testimony whereof I affix my signature.

ALEXANDER PATEBSUN.

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